<!DOCTYPE html>
<html>
<body>
&nbsp;
<div style="position:relative; width:300px; background:grey;">
  <div style="position:absolute; left:0; bottom:0px; width:250px; background:lime;">abs.pos.</div>
  <div style="float:left; width:200px; height:200px; background:cyan;"></div>
  <script>document.body.offsetTop;</script>
  <div style="clear:both;"></div>
</div>
<script>document.body.offsetTop;</script>      
</body>
</html>
